Create your own conference schedule! Click here for full instructions

Abstract Detail



Biogeography

Morris, Ashley B [1].

Which way did they go? Assessing biogeographic hypotheses in New World star anise.

Illicium (Schisandraceae) is a basal angiosperm genus exhibiting a series of intriguing geographic disjunctions throughout southeast Asia, eastern North America, and the Greater Antilles. Molecular and morphological studies have divided the group into monophyletic Old and New World clades, although resolution within the two clades remains elusive. Convergent morphology has resulted in conflicting taxonomic treatments, adding to confusion in this group. Divergence time estimates based on molecular work suggest that extant species are relatively young, further complicating our ability to define species boundaries. The objective of this study was to provide additional clarity to the relationships among New World Illicium species through phylogenetic reconstruction based on DNA sequence data. One accession of each of the seven recognized New World species was included in the present study: I. floridanum, I. mexicanum, I parviflorum, I ekmanii, I. hottense, I. cubense, and I. guajaibonense. Seven chloroplast DNA regions (atpB-rbcL, trnL intron, trnL-F spacer, psbA-trnH, trnQ-rps16, trnD-trnT, and psbK-I) and the nuclear ribosomal DNA internal transcribed spacer (ITS) region were sequenced for the ingroup species and for a single outgroup species, I. henryi, from China. These data were concatenated and analyzed in a Maximum Parsimony framework (MP). MP results recovered two main clades within the New World: 1) I. floridanum and I. mexicanum (100% bootstrap support); and 2) all other taxa (91 % bootstrap support). These results are consistent with current taxonomy recognizing two subsections on the basis of floral morphology, as well as with previous molecular studies. Within the second, larger clade (recognized as subsect. Parviflora), an additional subclade containing I. parviflorum and the two Cuban species was recovered with 86% bootstrap support. Additional accessions are currently being sequenced to confirm these results. Divergence time estimates will be performed on the completed data set using Illicium avitum from the Miocene of Vermont to calibrate the phylogeny in a Bayesian framework. Implications for New World biogeography will be discussed.

Broader Impacts:


Log in to add this item to your schedule

1 - Middle Tennessee State University, Department of Biology, 1301 E Main Street, Murfreesboro, TN, 37132, USA

Keywords:
Illicium
divergence time estimation
biogeography
Caribbean
Chloroplast DNA.

Presentation Type: Oral Paper:Papers for Topics
Session: 38
Location: Marlborough A/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 9:30 AM
Number: 38005
Abstract ID:382
Candidate for Awards:None


Copyright © 2000-2012, Botanical Society of America. All rights reserved